1. What is an API?
Answer:
An API (Application Programming Interface) is a set of protocols, routines, and tools that allow different software applications to communicate with each other. It acts as a messenger that delivers your request to the provider you’re requesting it from and then delivers the response back to you.
Examples of popular APIs include:
- Google Maps API (for embedding maps)
- Twitter API (for posting tweets programmatically)
- YouTube API (for accessing YouTube content programmatically)
APIs are crucial because they simplify programming by abstracting the underlying complexity of system operations.
2. What are the main differences between an API and a Web Service?
Answer:
- All web services are APIs, but not all APIs are web services.
- A Web Service is a type of API that operates over a network (like the internet).
- APIs can be used for both online (over a network) and offline (local system) communication.
- Web services typically use standards like SOAP, REST, or XML-RPC.
- APIs can use any communication style and don’t strictly require a network.
- Example: A local database API allows interaction without any network, but a web service like Weather API needs internet access.
3. What are the Limits of API Usage?
Answer:
APIs often come with usage limits set by the provider. These limits control how many API calls you can make in a day, per minute, or even per second to:
- Prevent server overload
- Manage cost
- Ensure fair usage across clients
If you exceed these limits, your access may be throttled or blocked temporarily, impacting any services dependent on that API.
Example: Google Maps API has a daily limit on map loads.
4. What are some architectural styles for creating a Web API?
Answer:
The common architectural styles for building Web APIs are:
- Client-Server Communication via HTTP
- Data formatting using XML or JSON
- Simple URI endpoints for accessing resources
- Statelessness — each request is independent, containing all necessary information.
APIs like RESTful APIs strictly follow these principles to maintain scalability and simplicity.
5. Who can use a Web API?
Answer:
Any client that supports HTTP operations (GET, POST, PUT, DELETE) can use a Web API.
This includes:
- Web browsers
- Mobile apps
- Embedded devices (IoT devices)
No special configuration is needed, making APIs widely accessible across various platforms and technologies.
6. What is API Testing?
Answer:
API Testing is a type of software testing where you test APIs directly — without involving the UI (User Interface).
In API testing, testers verify:
- Correctness of response
- Performance (how fast)
- Security (authentication, authorization)
- Reliability (stable under different conditions)
It ensures that APIs return the correct response for a wide variety of requests and behave as expected.
7. What are the advantages of API Testing?
Answer:
- Tests Core Functionality Early: Bugs in business logic are caught before GUI testing.
- Faster and Time-Efficient: No need to load the full user interface, making it faster.
- Language-Independent: APIs typically use data formats like XML or JSON, which are readable across different programming languages.
- Better Test Coverage: You can test edge cases and internal server errors directly.
- Easy Integration with GUI Tests: APIs can create the test data required for UI tests.
8. Some common protocols used in API Testing?
Answer:
Some common protocols used for API communication and testing are:
- HTTP/HTTPS (standard communication)
- REST (Representational State Transfer)
- SOAP (Simple Object Access Protocol)
- JMS (Java Message Service)
- UDDI (Universal Description, Discovery, and Integration)
Each protocol serves different needs based on the API’s architecture.
9. What is the Test Environment of API?
Answer:
Setting up an API testing environment involves:
- Setting up the server and database.
- Ensuring all necessary services are running.
- Configuring parameters like API keys, tokens, etc.
- No GUI is involved, so testing is done using tools like Postman, SOAP UI, or automation frameworks.
Testing happens by sending requests directly to the API endpoints and verifying responses.
10. What are principles of an API Test Design?
Answer:
Important principles for API Test Design are:
- Setup: Initialize servers, create required data.
- Execution: Send the API requests.
- Verification: Validate responses and outputs.
- Reporting: Document whether the API passed or failed.
- Clean-up: Restore the test environment to its original state.
Following these helps maintain an organized and reliable testing cycle.
👉The Next 10 Questions-I: API TESTING
